## Confidence Interval for Difference of Two Means Test

Unit Test #79

Select your answers to the following 5 questions from the pop-up menus in the right hand column. Clicking the "Begin Test Again" button will clear all the answers.

 Q1: What would be the equivalent z-score for a confidence level of 96%? A. 1.844 B. 0.1844 C. 2.054 D. 2.05 Answer 1: A                    B                    C                    D Q2: A sample of size 80 is taken from a population C with a mean of 55 and a standard deviation of 5.2. A sample of size 70 is taken from a population D with a mean of 51 and a standard deviation of 4.9. Find the standard deviation of ( - ) A. 0.367 B. 0.135 C. 0.825 D. 0.681 Answer 2: A                    B                    C                    D Q3: Find a 95% confidence interval for the difference of the means of populations C and D. A. (2.38, 5,62) B. (4.83, 3.17) C. (2.64, 5.36) D. (2.48, 5,52) Answer 3: A                    B                    C                    D Q4: Is there sufficient evidence to suggest that the means of populations C and D are different? A. Yes B. No Answer 4: A                    B                    C                    D Q5: A random sample of 100 oranges from the South Island has oranges with a mean weight of 240 g and a standard deviation of 40 g, whereas a sample of 100 oranges from the North Island has a mean weight of 210 g and a standard deviation of 30 g . The samples are independent and normally distributed. Construct a 90% confidence interval for the difference between the mean weights of the oranges in the two locations. A. (-11.1, 71.1) B. (21.8, 38.2) C. (22.3, 36.7) D. (20.2, 39.8) Answer 5: A                    B                    C                    D